Air New Zealand boss Christopher Luxon says investigating options for a second commercial airport in Auckland is not about putting the squeeze on the current operator - but about cheaper airfares and cutting the commute time for travellers.

The airline's revealed it's in the final stages of assessing the viability of flying out of the Defence Force owned Whenupai airbase in North West Auckland but hasn't yet discussed its proposal with the government.

Mr Luxon, who is set to leave Air NZ later this month, says customers tell him transport to Auckland airport is sub-optimal and a second airport could solve those issues.